Vibration damped fitting

ABSTRACT

A socket type end fitting for wire rope and strand is provided with a plastic cone intimately shaped about the strand adjacent to the fitting to dampen vibrations in the rope.

United States Patent Smollinger [54] VIBRATION DAMPED FITTING [72]Inventor: Carl W. Smollinger, 1621 Marlin Ave., Williarnsport, Pa. 17701[22] Filed: Dec. 31, 1969 [21] Appl. No.: 889,381

[52] US. Cl ..24/123, 339/101 [51] Int. Cl ..Fl6g 11/00 [58]FieldofSearch.....339/l01, 102,233; 24/l23.3,

[56] References Cited UNITED STATES PATENTS 1,871,308 8/1932 Dodge etal. ..24/1223 1 2,211,615 8/1940 Brickman et al. ..24/122.3

Brickman ..24/ 122.3

2,700,398 l/ 1955 Green ..24/115 2,766,317 10/ 1956 Woodward ..24/1232,945,457 7/ 1960 Avery et al. ..24/123 3,238,494 3/1966 Bentley..339/223 OTHER PUBLICATIONS Tuffy Sling Handbook, pages 5 8 and 59Primary Examiner-Bobby R. Gay Assistant Examiner-Garry MooreAttorney-Joseph J. OKeefe ABSTRACT A socket type end fitting for wirerope and strand is provided with a plastic cone intimately shaped aboutthe strand adjacent to the fitting to dampen vibrations in the rope v v11 Claims, 8 Drawing Figures P'ATE'NTED use 12 I972 saw 1 or 3 PATENTEDuse 12 I972 SHEET 2 BF 3 INVENTOR Carl W Sma/flnger PA'TENTED um: 12 m27 SHEET 3 BF 3 INVENTOR Car/ W. Smo/fl'nger VIBRATION DAMPED FITTINGBACKGROUND OF THE INVENTION This invention relates to the alleviation offatigue in wire ropes and strands by means of vibration and particularlyto the provision of vibration damping means on a socket type endfitting.

Wire rope and strand subjected to repeated shock and widely fluctuatingloads, such as occurs in large earth moving machinery is often subjectto premature failure due to wire fatigue. Fatigue of the wires of thestrand is particularly'liable to occur at or adjacent to fittingsmounted on the strand. This is due to the concentration of stress in thestrand adjacent the fitting due to repeated torque and sinusoidalvibrations caused by repetitive cycles of loading and unloading.

Various expedients havebeen resorted to in the past to decrease suchvibrations but none to the present inventors knowledge has beenparticularly successful with the exception of the damper previouslydisclosed SUMMARY THE INVENTION In accordance with the invention ametallic end fitting such as a hot metal socket type fitting or acompression type fitting has mounted upon the end thereof and secured ormolded in intimate contact with the surface of a cable upon which thefitting is mounted, a plastic damper body preferably in the shape of acone tapered away from the fitting. This plastic damper body or conedamps out vibrations in the strand and allows the tensional forces inthe strand to be evenly transferred into the metallic body of thefitting.

The damper assembly disclosed in application Ser. No. 807,635 isparticularly effective with, though not limited to use with,-largediameter wire ropes. The applicants present damper'arrangement has beenfound particularly effective with, though by no means limited to usewith, smaller diameter wire ropes.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric view of afitting according to the present invention and an accompanying splitmold shown exploded for clarity.

FIG. 2 is a longitudinal cross-section through the fitting shown in FIG.1.

FIG. 3 is a modification of the fitting shown in FIG. 1. 1

FIG. 4 is a cross-section through a compression type fitting accordingto the present invention.

FIG. 5 is a view of amodification of the invention.

FIG. 6 is an end view of FIG. 5. a

FIG. 7 is a view of a further modification.

.FIG. 8 is an end view of FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A zinc socket type end fitting11 is shown in FIGS. 1 and 2. As well understood in the art this fittinghas a bowl 13 at one end into which a wire rope or strand 15 is insertedthrough an orifice 17 in the bottom of the fitting. The individual wiresor strands of the strand or rope 15 are partially unlaid and broomedoutwardly within the bowl and molten zinc or other suitable molten metal19 is poured into the bowl around the wires or strands and allowed tosolidify.

A flange 21 is positioned on the bottom of socket 11 preferably inclinedinwardly toward the strand 15' to form a hollow frustum. Flange 21 ispreferably formed as an integral portion of the socket 11 but may, ifdesired, be welded onto the socket.

After the strand or rope 15 is fixed in the socket 11 the lower portionof the socket is placed within a conical mold 23 which is preferablymade in two sections 25 and 27 as shown in partial exploded view inFIG. 1. The two sections 25 and 27 of the mold fit over the flange 21and define a conical internal mold chamber 29 into which a moltenthermoplastic or a thermosetting plastic is poured through orifice 31.Any suitable plastic which is firm, resilient, tough, shock resistantand preferably transparent may be used. A polyurethane plastic has beenfound particularly suitable. The hardness .of the plastic should bebetween and 95 on the Durometer A scale and will preferably have ahardness of between and 92 on the Durometer A scale. Durometer scale Ais substantially identical to the well known Shore A scale and readingson both scales are interchangeable.

After the plastic has solidified orset the mold 23 is removed leaving aconical plastic damper 33 firmly locked to the strand or rope andextending away from the bottom of the fitting. This plastic damper 33absorbs vibrations in the strand by smoothing them out and allowing thetension of the strand to be evenly transferred to the body of thefitting.

As a modification of the method of forming the conical damper 33 athermoplastic cone having a central orifice larger than the diameter ofthe strand or rope and outside dimensions greater than the finaldimensions of the conical damper can be placed over the rope or strandand then forced partially down within the flange 21. After beingpositioned the cone may be enclosed in a heated mold which will softenthe plastic of thecone and enable it to be firmly forced into lockingengagement with the flange .21 and firmly molded about strand or rope15. The initial thermoplastic cone may be split lengthwise in order tofacilitate its placement about the strand.

FIG. 3 shows a modification of the damper arrangement in which flange 21is discontinuous, or has orifices 35 in it, so that the strand 15 can beperiodically inspected through the transparent plastic to detect anydamage to the portion of the strand entering the bottom of the socket.

FIG. 4 is a cross-section through a compression type end fitting havinga body portion 37 firmly compressed by swaging or the like upon the endof a strand and a conical plastic damper 39 firmly molded to the strandand extending away from the bottom of the body of the fitting. Thecompression fitting is adapted to be secured to the strand by forceapplied over most of the body of the fitting up to dotted line 41 butnot over the terminal end 43 of the fitting. The terminal end 43 of thecompression fitting beyond dotted line 41 has an initial slight internaltaper which is outwardly inclined prior to compression. When bodyportion 37 is compressed by swaging or other equivalent force theterminal end 43, which is not compressed, flares outwardly still furtherproviding a tapered opening 45 between the strand and the terminal end43. If desired a slight inward curvature or head 47 may be providedaround the inner lip 49 of the terminal end 43. When the plastic cone 39is subsequently molded over the strand in the same manner as shown inFIGS. 1 and 2 for a hot metal type socketi locks intimately with thesurface irregularities of the strand and is wedged between the outwardlyflared terminal end 43 of the swaged fitting and the strand. Since thestrand and the plastic cone 39 is also molded or locked intimately tothe strand the cone and the fitting are firmly secured together inintimate contact with each other through the strand even though theopening strand adjacent to and preferably tightly butting a fitting andclamped securely to the strand in intimate contact therewith by anysuitable clamping means. In

' this arrangement the fitting and the plastic cone are both locked tothe strand and thus securely fastened to each other through the strand.Preferably the plastic damper body will also be clamped to the nose ofthe fitting. Considerable vibration is thus absorbed by the plastic conebefore reaching the fitting and fatigue of the strand wires near thefitting is considerably reduced. While this embodiment of the inventionis not nearly as efficient an arrangement as having the plastic coneintimately molded to the strand it may at times be useful for emergencyfield application, particularly where the fatigue life of the rope orstrand need not be greatly prolonged because the strand is exposed toother deleterious conditions which will cause accelerated failure in anyevent.

Temporary plastic damper bodies suitable for field application are shownin FIGS. 5 and 6, 7 and 7 and 8. In FIGS. 5 and 6 a conventional moltenzinc socket 61 has been previously secured to a strand 63. Two halves 65and 67 of a plastic damper body 69 formed from a polyurethane plasticand preferably having a hardness on the Durometer A scale of fromapproximately 90 to 95 have then been secured by bolts 71 about thestrand 63 adjacent to socket 61 with flanges 73 extending over andaround the nose of the socket in intimate contact therewith. The twohalves 65 and 67 of the plastic damper body 69 must be firmly secured tothe surface of the strand 63 by tension in the bolts 71. Preferably theinner surfaces of the damper body contacting the strand will bepreviously contoured to conform to the helical surface of the strand.Flanges 73 are rounded in contour so that a commercial type strapping orthe like may be placed about the flanges to clamp them to the nose ofthe fitting if necessary to obtain an intimate contact between fitting61 and damper body 69.

In FIGS. 7 and 8 there is shown a second embodiment of a temporaryplastic damper body 75 secured about a zinc socket fitting 77 and astrand 79 by means of straps 81 and 83 applied over flange section 85and nose 87 of two halves 89 and 91 of plastic damper body 75. A smallopening 93 may be formed within the plastic damper body adjacent thenose of the fitting to contain lubricant.

While it would be desirable if the temporary plastic damper bodies 69and were conical in shape they need not be because they are intended tobe temporary expedients only and cannot be expected in any event todelay fatigue in the wires of the strand for extended periods. Ease offabrication and application to the strand in the field may thus outweighother design considerations. In environments where fatigue occurs veryquickly as in some large shovel and crane strands it may be sufficientif by the application of the dampers in the field the strand lasts twoweeks or more rather than only a week. A conical damper body intimatelymolded about the strand as in FIGS. 1 through 4 on the other hand mightpreserve the strand under the same conditions for as much as a month ormore. In each case transverse vibrations in the strand are imparted tothe plastic damper body as they progress towards the fitting and arepassed on to the fitting with very materially reduced amplitude andenergy due to the vibration absorption properties of plastic materialhaving the correct hardness and resiliency properties.

I claim: v

1. An end fitting for a wire cable subject to destructive vibrationswhile tensioned during use comprising:

a. afirst metallic body portion of said fitting secured upon the end ofa wire cable, and Y b. a second elongated plastic damper body portioncomprised of a substantial body of plastic material positionedimmediately adjacent to the said first body portion in the direction ofthe axis of the said cable and in intimate contact with said firstmetallic body portion; said second plastic damper body extending beyondsaid first metallic body portion along the cable for a distancesubstantially less than the length of the cable in intimatecircumferential contact with the peripheral surface of the wire cableand the component peripheral wires thereof and comprising a stiffresilient plastic material selected from the group consisting ofthermoplastic and thermosetting resins.

2. An end fitting for a wire cable subject to destructive vibrationswhile tensioned during use comprising:

a. a first metallic body portion of said fitting secured upon the end ofa wire cable,

b. a second elongated plastic damper body portion of said fittingcomprised of a substantial body of plastic material positionedimmediately adjacent to the said first body portion in the direction ofthe axis of the said cable and in intimate contact with said firstmetallic body portion; said second plastic damper body extending awayfrom said first metallic body portion along the cable in intimatecircumferential contact with the peripheral surface of the wire cableand the component peripheral wires thereof and comprising a firmresilient plastic material selected from the group consisting ofthermoplastic and thermosetting resins, and

c. plastic gripping means attached to said first body portion to firmlysecure the second plastic damper body to the said first metallic bodyportion.

3. An end fitting according to claim 2 wherein the portion of the secondplastic damper body of (b) extending along the cable is comprised of aplastic having a Durometer A hardness of 70 to 95..

4. An end fitting according to claim 3 wherein the outer surface .of theportion of the second plastic damper body of (b) extending along thecable is significantly tapered in a direction away from said bodyportion.

5. An end fitting according to claim 4 wherein the outer surface of theportion of the second plastic damper body of (b) extending along thecable is generally conical in shape.

6. An end fitting according to claim 5 wherein the outer portion of thesecond plastic damper body of (b) is comprised of a plastic having aDurometer A hardness of 80 to 92.

7. An end fitting according to claim 6 wherein the plastic grippingmeans of (c) comprises an annular flange secured to said first metallicportion arranged to effectively surround a section of said secondplastic body portion adjacent to said first metallic body portion tosecurely attach the two portions together.

8. An end fitting according to claim 7 wherein the first metallic bodyportion of (a) comprises a hot metal type socket.

9. An end fitting according to claim 4 wherein the first metallic bodyportion of (a) comprises a compression type fitting.

10. An end fitting according to claim 9 wherein the portion of thesecond plastic body portion of (b) extending along the cable iscomprised of a plastic having a Durometer A hardness of to 92.

11. An end fitting according to claim 8 wherein the plastic comprisingthe section of the second plastic damper body of (b) surrounded by saidannular flange is at least partly transparent and the annular flange isdiscontinuous.

1. An end fitting for a wire cable subject to destructive vibrationswhile tensioned During use comprising: a. a first metallic body portionof said fitting secured upon the end of a wire cable, and b. a secondelongated plastic damper body portion comprised of a substantial body ofplastic material positioned immediately adjacent to the said first bodyportion in the direction of the axis of the said cable and in intimatecontact with said first metallic body portion; said second plasticdamper body extending beyond said first metallic body portion along thecable for a distance substantially less than the length of the cable inintimate circumferential contact with the peripheral surface of the wirecable and the component peripheral wires thereof and comprising a stiffresilient plastic material selected from the group consisting ofthermoplastic and thermosetting resins.
 2. An end fitting for a wirecable subject to destructive vibrations while tensioned during usecomprising: a. a first metallic body portion of said fitting securedupon the end of a wire cable, b. a second elongated plastic damper bodyportion of said fitting comprised of a substantial body of plasticmaterial positioned immediately adjacent to the said first body portionin the direction of the axis of the said cable and in intimate contactwith said first metallic body portion; said second plastic damper bodyextending away from said first metallic body portion along the cable inintimate circumferential contact with the peripheral surface of the wirecable and the component peripheral wires thereof and comprising a firmresilient plastic material selected from the group consisting ofthermoplastic and thermosetting resins, and c. plastic gripping meansattached to said first body portion to firmly secure the second plasticdamper body to the said first metallic body portion.
 3. An end fittingaccording to claim 2 wherein the portion of the second plastic damperbody of (b) extending along the cable is comprised of a plastic having aDurometer A hardness of 70 to
 95. 4. An end fitting according to claim 3wherein the outer surface of the portion of the second plastic damperbody of (b) extending along the cable is significantly tapered in adirection away from said body portion.
 5. An end fitting according toclaim 4 wherein the outer surface of the portion of the second plasticdamper body of (b) extending along the cable is generally conical inshape.
 6. An end fitting according to claim 5 wherein the outer portionof the second plastic damper body of (b) is comprised of a plastichaving a Durometer A hardness of 80 to
 92. 7. An end fitting accordingto claim 6 wherein the plastic gripping means of (c) comprises anannular flange secured to said first metallic portion arranged toeffectively surround a section of said second plastic body portionadjacent to said first metallic body portion to securely attach the twoportions together.
 8. An end fitting according to claim 7 wherein thefirst metallic body portion of (a) comprises a hot metal type socket. 9.An end fitting according to claim 4 wherein the first metallic bodyportion of (a) comprises a compression type fitting.
 10. An end fittingaccording to claim 9 wherein the portion of the second plastic bodyportion of (b) extending along the cable is comprised of a plastichaving a Durometer A hardness of 80 to
 92. 11. An end fitting accordingto claim 8 wherein the plastic comprising the section of the secondplastic damper body of (b) surrounded by said annular flange is at leastpartly transparent and the annular flange is discontinuous.